Question

the point (-5,3) is the center of the circle and P (7,-2) lies on the circle.the radius of the circle is ?

Answer 1

radius = 13

Explanation:

the radius r is the distance from the centre to a point on the circle

calculate r using the distance formula

r =
`\sqrt{(x_(2)-x_(1))^2+(y_(2)-y_(1))^2 }`

with (x₁, y₁ ) = (- 5, 3 ) and (x₂, y₂ ) = (7, - 2 )

substitute these values into the formula

r =
`√((7-(-5))^2+(-2-3)^2)`

=
`√((7+5)^2+(-5)^2)`

=
`√(12^2+25)`

=
`√(144+25)`

=
`√(169)`

= 13